Doing a double take:  Hemispheric contributions to language processing

Kara D. Federmeier
University Scholar and College of LAS Centennial Scholar, Department of Psychology, Program in Neuroscience,
and Beckman Institute for Advanced Science and Technology University of Illinois

Event-related potential studies have revealed that, when it can, the brain uses context to predict features of likely upcoming items. However, although prediction seems important for comprehension, it also appears susceptible to age-related deterioration and can be associated with processing costs. The brain may address this trade-off by flexibly employing multiple processing strategies, distributed across the two cerebral hemispheres. In particular, left hemisphere language processing seems to be oriented toward prediction and the use of top-down cues, whereas right hemisphere comprehension is more bottom-up, biased toward the veridical maintenance of information. Such asymmetries may arise, in turn, because language comprehension mechanisms are integrated with language production mechanisms that are biased toward the left hemisphere (the PARLO framework).